South Korea Fines KT Corp. 53.9 Billion Won Over Data Breach
SEOUL — South Korea's privacy watchdog has fined wireless carrier KT Corp. 53.9 billion won (US$37.4 million) over a major data breach that affected more than 16,000 users, Yonhap reported Thursday.
The Personal Information Protection Commission also ordered KT to take corrective measures regarding the breach, which occurred through unauthorized mobile base stations.
The breach, first reported by the company in September, compromised phone numbers and mobile device identification numbers of 16,647 users, according to the regulator. Malicious actors used the information to carry out unauthorized transactions, resulting in total losses of 240 million won for 368 victims.
The watchdog said hackers accessed KT's wireless network unnoticed between Oct. 8, 2024, and Sept. 5, 2025, and the company only realized the breach had occurred after a user complaint. The hackers gained access by building illegal base stations using authentication certificates extracted from base stations that KT had lost.
The regulator ordered KT to strengthen security measures for its wireless network equipment and personal information protection.
Additionally, the watchdog decided to file a complaint with police against KT for obstructing its investigation into a separate hacking incident in March 2024 that the company did not report to authorities. The company initially denied keeping records of the incident, in which its servers were infected with malicious code, but later handed them over after the regulator found signs of evidence tampering.
The watchdog also separately referred another telecom operator, LG Uplus Corp., to police for investigation on suspicion of obstruction of official duties after determining the company had covered up or destroyed records of a data leak.
KT's Second-Quarter Earnings Hit by Fines
On Aug. 12, KT Corp. reported that its second-quarter net income fell 34.5 percent from a year earlier, attributing the decline to the government fines from the massive data breach.
The company's net income for the April-June period on a consolidated basis was 480.6 billion won (US$339.9 million), according to its regulatory filing. Operating profit fell 36.1 percent to 648.3 billion won, and sales dropped 10.1 percent to 6.68 trillion won.
KT attributed the sharp decline in net income to the 54 billion won in government fines. Operating profit also fell year-on-year due to costs related to its consumer compensation program, but improved from the previous quarter amid a recovery of its business-to-business unit.
Notably, its artificial intelligence (AI) and cloud business grew by 22.3 percent from a year earlier, as more companies, especially from the financial sector, adopted its AI-related infrastructure.
"We plan to continue growth focusing on our core portfolio, while also strengthening our customer data protection and security capabilities to build customer trust and enhance corporate value," the company said in a release.
KT plans to increase sales from its AI infrastructure and solution businesses to double the amount seen in 2025 by 2028. It aims to secure an additional 1 gigawatt capacity in AI data centers and 90 terabits per second capacity in submarine cables by 2031.
The company also said it is in the final stages of completing a 250 billion-won stock buyback plan announced in February, with the planned deadline set for Sept. 9.